package fr.neyb.bernouilli.problem015;



public class Entry {

	private final static int size = 20;

	public static void main(String... args) throws Exception {
		long[] suite = new long[size + 1];
		suite[0] = 1;
		suite[1] = 2;
		for (int i = 2; i <= size; ++i) {
			for (int j = 1; j <= i; ++j) {
				if (i == j) {
					suite[j] = 2 * suite[j - 1];
				} else {
					suite[j] += suite[j - 1];
				}
			}
		}
		System.out.println(suite[size]);
	}

}
